Table 1 Description of variables used in this study
Variable | Levels | Description |
|---|---|---|
Health outcomes | ||
Self-reported health (SRH) | Good health - 0 | · General health rated as very good, good, fair, bad or very bad |
Poor health −1 | · Good health recoded as very good or good | |
· Poor health recoded as fair, bad, very bad | ||
Limiting longstanding illness (LLI) | No LLI - 0 | Respondents asked if they had a limiting-longstanding illness |
LLI - 1 | · No LLI | |
· Have LLI | ||
Mental health | Good mental health - 0 | Score from the 12-item General Health Questionnaire (GHQ-12). |
Poor mental health - 1 | · Score 0–3 recoded as good mental health | |
· Score 4 or more recoded as poor mental health | ||
Lung function | Good lung function - 0 | Three questions related to respiratory symptoms were asked resulting in the variable ‘wheezed without a cold’. |
Poor lung function - 1 | · Not ‘wheezed without a cold’ recoded as good lung function | |
· ‘Wheezed without a cold’ recoded poor lung function | ||
Smoking status | Non-smoker - 0 | Smoking history |
Smoker - 1 | · Non-smoker | |
· Current smoker | ||
Alcohol consumption | Under and including limits - 0 | Weekly alcohol consumption (weekly limits: males 21 units, females 14 units) |
Over weekly limits - 1 | · Under and including limits | |
·` Over weekly limits | ||
Explanatory variable | ||
Employment status | Employed −1 | Employment status at time of interview |
Unemployed - 2 | ||
Permanently sick - 3 | ||
Looking after home and family - 4 | ||
Others – 5 | ||
Confounding variables | ||
Sex | Male – 1 | Sex of the respondent |
Female – 2 | ||
Age | 16-24 - 1 | Age of respondent |
25–34 - 2 | ||
35–44 - 3 | ||
45–54 - 4 | ||
55–64 - 5 | ||
Deprivation (SIMD quintile) | Scale 1 to 5 | The Scottish Index of Multiple Deprivation (SIMD), an area-based level of deprivation, was derived from the residential postcode of the respondents and categorised into quintiles. The SIMD score is calculated at the level of “data zones” using 31 indicators in six individual domains of current income, employment, housing, health, education, skills and training and geographic access to services and telecommunications. Data zones are groups of Census output areas which have populations of between 500 and 1,000 residents. |
Least deprived - 1 | ||
Most deprived - 5 | ||
Education | Degree or higher −1 | Highest level of qualification obtained |
Higher National Certificate/Diploma (HNC/D) or equivalent - 2 | ||
Higher grade or equivalent - 3 | ||
Standard grade or equivalent - 4 | ||
Other school level - 5 | ||
None - 6 | ||